(cba:news) MASTER OT J040552.59+274716.7, and others
jop at astro.columbia.edu
Tue Sep 10 01:15:10 EDT 2013
I'm a little communications-hampered here in Sicily for a CV
conference... but this (details below, but also see ATEL 5369)
definitely looks like it's up our alley. Decently well-positioned,
easily good enough for deciphering aliases with a longitude spread among
our observatories. Fire away with the usual approach - time series
photometry in unfiltered light, preferably with time resolution of 50-80
s or better.
Re other stars. V1101 Aql continues to delight, but is now coming off
another max, and I'd suggest continuing coverage for just one more week,
then quitting. I think the filtered-photometry approach can be ended
now. At first glance, the data suggest the usual result for CVs: the
periodic signals are white (and thus no significant advantage in using
filters - except for very bright targets of course).
NR TrA can also be ended now. It was an experiment in defying the
onrushing evening twilight. Those experiments always lose in the end...
and besides, we got great results. Berto, Josch, Bob Rea, and Gordon
Myers manned the ramparts. It amazes me how these "young old novae"
have such similar orbital light curves - while all the old guys (novae
>50 years ago) revert to their own characteristic and highly varied
BW Scl is definitely worth continuing. It shows strong "high-epsilon"
or "2:1" superhumps - signals exceeding Porb not by ~2%, but more like
7-8%. This phenomenon still doesn't have a name, and most CV
astronomers have never heard of it. It's time for us to write a really
good paper about them, and I think BW Scl is the ideal excuse for it,
because the waves are quite strong, with maxima visible in the light
curve (therefore easily timed). Berto, Josch, and Bob Rea have been
steadily observing. With some coverage from Greg Bolt (Perth) and
Arto(Chile, but with high density of points), we could track this all
the way around the globe. The reason that's highly desirable - rather
than just a point of pride - is that the waves are *much less stable in
phase* than their better-known 3:1 cousins, regular old superhmps. So
we gotta track them more closely, at least some of the time.
Enrique has begun the year's coverage on PX And, and it's also time (or
almost time?) to begin on LT Eri and AH Men. Each of these stars shows
positive superhumps, negative superhumps, and "nodal precession" (or
anyway, a long-period signal at the beat frequency of orbit and negative
superhump. Or at least they did at some point in our scattered coverage
in past years. It's time (or maybe almost time - it depends on whether
you like morning observing!) for an *intensive* campaign which will nail
these results down.
Finally, I plead again for coverage of V1494 Aql. Remember that
brilliant star in November 1999? Let's give it some love now!
Enrique's data confirm the (somewhat shallow) eclipses, and I think also
the double-humped light curve that may yield the temperature of the
still-hot-and-glowing white dwarf. Can't tell yet re superhumps. It's
about 17.2, a pretty hard target - but can be done in good conditions by
many of you.
Oops, also finally... ASAS-SN13ck is turning out great! Keep the
campaign going on that star. BTW my email access is very poor here, and
I hope you guys with actual telescopes and live computers will use
cba-chat and cba-news to communicate useful stuff in the next 7-10 days,
esp. as regards these new or lesser-known targets.
-------- Original Message --------
Title: Spectroscopy of MASTER OT J040552.59+274716.7 in Taurus
Author: R. M. Wagner (Ohio State), C. E. Woodward (Minnesota), and
S. G. Starrfield (Arizona State)
Queries: mwagner at lbto.org
Posted: 9 Sep 2013; 16:53 UT
Subjects:Optical, Cataclysmic Variable, Nova, Transient
We observed the optical transient designated MASTER OT J040552.59+274716.7
reported by Denisenko et al. (ATEL #5369) on 2013-09-06.4090 UT with the
2.4 m Hiltner telescope on Kitt Peak, Arizona. We confirm the presence
of a bright transient at the position reported by Denisenko et al.
we obtained several spectra of the transient using the OSU CCD Spectrograph
(CCDS; range: 366-730 nm; resolution: 0.9 nm). The average spectrum
emission lines of the Balmer series of hydrogen; He I 706.5, 667.8, 587.5
nm; He II 468.6 nm; and perhaps N III 464.0 nm. The equivalent width of
H-alpha emission was 1.60 nm and with a FWHM of 1.32 nm (corrected for
instrumental resolution). In addition, weaker H-beta and several of the
higher order Balmer emission lines are superposed on broad (full-width
of 6.2 nm at H-beta) absorption troughs. The spectrum is characteristic
of a dwarf nova near maximum light. The appearance of the spectrum and
outburst amplitude of at least 7.5 mag reported by Denisenko et al. suggests
that the transient is a member of the WZ Sge subclass. Further
photometric observations are encouraged.
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